The easiest 4 of this collection are the ones outside the bottles. The others are in the Duos & Alerts of this set. It is possible to sneak in on your own & locate the briefings without too much combat, but study the location images above & use the Radar Scanner to locate them. The use Warp HQ if you get ‘caught’ by the Brainiac forces.

The hardest to find is the one in the Gotham Courthouse T3 Alert. You have to defeat the ground forces & wait for the mission to ‘deactivate’ the ‘gravity generators’ that prevent you from leaving ground-level. Once you’re free to fly/scale/climb, explore at the top of the Courthouse spire. You may miss it the first couple of times you scout for it, as where it is is brightly lit up & the blue glow of the Briefing can be washed out at several angles.